Level-Shifted Sense Amplifier for Low-Voltage Memory Sensing

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Solution Overview

Problem

Traditional sense amplifiers for nonvolatile memory cells consume high energy due to differential sensing methods, which are designed for higher voltage domains, leading to increased energy consumption.

Innovation Solution

A system that shifts high voltage analog signals to a low voltage domain using a level shifter, eliminating the need for high voltage drivers and level shifters, allowing sensing operations to be performed in a low voltage domain with reduced energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If differential sensing is used for nonvolatile memory cells, then sensing accuracy is improved, but energy consumption increases significantly

Engineering Contradiction:

Improvesensing accuracyVSAvoidenergy consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The sensing operation is segmented into two independent phases: a first sensing operation that charges a first node based on the memory cell state, and a second sensing operation that reads the voltage at the first node. This segmentation allows each phase to use optimized circuit configurations, reducing overall energy consumption while maintaining accuracy through sequential measurement steps.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The sense amplifier dynamically reconfigures its circuit configuration between the two sensing operations. During the first operation, the amplifier is configured to charge the first node; during the second operation, it is reconfigured to read the voltage. This dynamic adaptation allows the same hardware to perform different functions efficiently, reducing energy consumption compared to static differential sensing circuits.

Inventive Principle:

Principle #15Dynamics

2Reliability

If high voltage domain sensing is used, then nonvolatile memory cell signals can be sensed, but power consumption increases

Engineering Contradiction:

Improvesensing capabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by stationary object

Solution Approach 1:

A coupling capacitor serves as an intermediary element between the high-voltage memory cell and the low-voltage sense amplifier. This capacitor transfers the voltage signal from the high-voltage domain to the low-voltage domain without requiring the sense amplifier to operate at high voltage, thereby enabling reliable sensing while operating in the lower power consumption voltage domain.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes the voltage domain parameter by performing sensing operations in a low voltage domain rather than the traditional high voltage domain. The memory cell operates at high voltage to maintain reliability, but the sensing and read operations are performed at low voltage using the coupling capacitor interface, significantly reducing power consumption during these operations.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP3799048B1Low voltage, low power sensing based on level shifting sensing circuit

Publication Date: 2023.05.17 INTEL CORP

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AI summary

A sensing circuit for sensing an analog signal includes a level shifter that shifts the analog signal from a high voltage domain to a low voltage domain. The signal originates from the high voltage domain, and is passed to the low voltage domain through the level shifter. A source line provides the analog signal, which can be selectively switched into a sense amplifier circuit. The sense amplifier is in the low voltage domain and generates a digital output to represent the sensed analog signal.